Socrates

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The Greek philosopher Plato, author of the Socratic dialogues.

Apology, 4th century B.C.

Facing charges of "corrupting youth," Socrates delivered this speech  as
rendered by Plato  to an Athens jury. It proved unsuccessful; he was
convicted by his peers, and subsequently killed himself by swallowing
hemlock. But this skillful piece of rhetoric underlines the realization that
has propelled philosophy ever since: that human knowledge is woefully
limited.